Now solar power has had its problems in recent decades. For years, solar panels were too expensive to compete. More recently, as we heard earlier in the business news, solar panels got so cheap that manufacturers ran into trouble. But solar energy had a signal achievement in March, and that is our last word in business today.

STEVE INSKEEP, HOST:

For the first time ever, all of the new electricity generation added to the nation's power grid in the month of March came from solar installations. That's according to the Federal Energy Regulatory Commission's monthly report on new power sources.

Seven solar installations went online adding 44 megawatts of generating power. Other forms of electric power generation did not grow at all in March.

GREENE: According to the agency, it has been a good year so far for renewable projects. Wind energy and natural gas have also grown since the start of this year.